BUG: Fix python 2.4 invalid use of try..finally.

In numpy/distutils/system_info.py
BUG: Fix Python 2.4 invalid class declaration and try..finally.

In numpy/lib/tests/test_regression.py
BUG: Fix invalid value warning raised during tests.

In numpy/core/numeric.py.
Merge pull request #4049 from charris/python-2.4-repair

Python 2.4 repair